Abstract: At approximately 1:20 a.m. on September 11, 1990, Employee #1, of Alaska Airlines, stepped from the intake cowling of a McDonnell Douglas DC9 MD-80 fuselage mounted engine onto a new 10 in. aluminum stepladder to which wheels and floor lock devices had been added by the employer. The ladder rolled and Employee #1 fell from the third or fourth step from the top to the concrete runway. He hit his head and died on September 12, 1990. The medical examiner listed the cause of death as contusions of the brain and fractures of the skull. Employee #1 and a coworker had unsuccessfully attempted to apply the floor lock devices (model #53-008), which were manufactured by the Tilden Corporation of Lenexa, KS, before starting the project. Employee #1 decided to use the ladder without blocking the wheels. Additional instructions were not affixed to the modified ladder. The floor locks did not operate as described by the manufacturer's representative.